Linear position sensing employing two geartooth sensors, a helical gear and a spur gear

Abstract

Methods and systems for detecting the linear movement of a shaft utilizing at least two geartooth sensors and two gears, one helical gear and one a normal spur gear are disclosed. As the shaft and gears translate in a linear direction, they are also rotating. Due to the fact one gear is a helical gear and the other is not, as the shaft translates mechanically, there will be a change in the phase between the output of a first geartooth sensor with respect to the second geartooth sensor. This change in phase is converted into linear travel using a simple calculation to detect the linear translation of the shaft.

Having thus described the invention what is claimed is:  
     
         1 . A method for detecting a linear movement of a shaft, said method comprising the steps of: 
 connecting a shaft to a first gear and a second gear, wherein said first and second gears are respectively associated with a first sensor and a second sensor;    rotating said shaft and said first and second gears in a rotatable direction while said shaft and said first and second gears simultaneously translate mechanically in a linear direction perpendicular to said rotatable direction, thereby generating a change in a phase between an output of said first sensor and an output of said second sensor; and    converting said change in phase into a linear travel value that provides an indication of a linear translation of said shaft.    
     
     
         2 . The method of  claim 1  further comprising the step of: 
 configuring said first gear as a spur gear.  
 
     
     
         3 . The method of  claim 1  further comprising the step of: 
 configuring said second gear as a helical gear.  
 
     
     
         4 . The method of  claim 1  further comprising the step of: 
 associating said first gear with a geartooth sensor.  
 
     
     
         5 . The method of  claim 1  further comprising the step of: 
 associating said second gear with a geartooth sensor.  
 
     
     
         6 . The method of  claim 1  further comprising the steps of: 
 configuring said first gear as a spur gear;  
 configuring said second gear as a helical gear;  
 associating said first gear with a geartooth sensor; and  
 associating said second gear with a geartooth sensor.  
 
     
     
         7 . The method of  claim 1  further comprising the step of: 
 locating said first and second gears remotely from one another.  
 
     
     
         8 . The method of  claim 7  further comprising the step of: 
 locating said first and second sensors separately from one another.  
 
     
     
         9 . The method of  claim 1  wherein said shaft comprises a shaft adapted for use with an internal combustion engine.  
     
     
         10 . The method of  claim 9  further comprising the step of: 
 detecting said translation of said shaft in order to alter an opening and closing of an engine valve associated with said internal combustion engine in response to a an engine condition thereof.  
 
     
     
         11 . The method of  claim 1  wherein said engine condition thereof comprises a load associated with said engine.  
     
     
         12 . The method of  claim 1  wherein said engine condition thereof comprises a speed associated with said engine.  
     
     
         13 . The method of  claim 1  wherein said shaft comprises a rotatable shaft.  
     
     
         14 . A method for detecting a linear movement of a shaft, said method comprising the steps of: 
 connecting a shaft to a spur gear and a helical gear, wherein said spur gear and said helical gear are respectively associated with a first geartooth sensor and a second geartooth sensor;    rotating said shaft and said spur gear and said helical gear in a rotatable direction while said shaft and said spur gear and said helical gear simultaneously translate mechanically in a linear direction perpendicular to said rotatable direction, thereby generating a change in a phase between an output of said first geartooth sensor and an output of said second geartooth sensor; and    converting said change in phase into a linear travel value that provides an indication of a linear translation of said shaft.    
     
     
         15 . A system for detecting a linear movement of a shaft, said system comprising: 
 a shaft connected to a first gear and a second gear, wherein said first and second gears are respectively associated with a first sensor and a second sensor;    a rotating mechanism for rotating said shaft and said first and second gears in a rotatable direction while said shaft and said first and second gears simultaneously translate in a linear direction perpendicular to said rotatable direction, thereby generating a change in a phase between an output of said first sensor and an output of said second sensor; and    a converting mechanism for converting said change in phase into a linear travel value that provides an indication of a linear translation of said shaft.    
     
     
         16 . The system of  claim 15  wherein said first gear comprises a spur gear.  
     
     
         17 . The system of  claim 15  wherein said second gear comprises a helical gear.  
     
     
         18 . The system of  claim 15  wherein said first gear is associated with a geartooth sensor.  
     
     
         19 . The system of  claim 15  wherein said second gear is associated with a geartooth sensor.  
     
     
         20 . The system of  claim 15  wherein: 
 said first gear comprises a spur gear;  
 said second gear comprises a helical gear;  
 said first gear is associated with a geartooth sensor; and  
 said second gear is associated with a geartooth sensor.  
 
     
     
         21 . The system of  claim 15  wherein said first and second gears are located remotely from one another.  
     
     
         22 . The system of  claim 21  wherein said first and second sensors are located separately from one another.  
     
     
         23 . The system of  claim 15  wherein said shaft comprises a shaft adapted for use with an internal combustion engine.  
     
     
         24 . The system of  claim 23  further comprising: 
 a detecting mechanism for detecting said translation of said shaft in order to alter an opening and closing of an engine valve associated with said internal combustion engine in response to a an engine condition thereof.  
 
     
     
         25 . The system of  claim 15  wherein said engine condition thereof comprises a load associated with said engine.  
     
     
         26 . The system of  claim 15  wherein said engine condition thereof comprises a speed associated with said engine.  
     
     
         27 . The system of  claim 15  wherein said shaft comprises a rotatable shaft.  
     
     
         28 . A system for detecting a linear movement of a shaft, said system comprising: 
 a shaft connected to a spur gear and a helical gear, wherein said spur gear and said helical gear are respectively associated with a first geartooth sensor and a second geartooth sensor;    a rotating mechanism for rotating said shaft and said spur gear and said helical gear in a rotatable direction while said shaft and said spur gear and said helical gear simultaneously translate in a linear direction perpendicular to said rotatable direction, thereby generating a change in a phase between an output of said first geartooth sensor and an output of said second geartooth sensor; and    a converting mechanism for converting said change in phase into a linear travel value that provides an indication of a linear translation of said shaft.